I think I'm in trouble.?

I don't really know what sucide thoughts are. What I've been having are not thought of wanting to do it but I think... I could do it. And i could end it here.... But I have been depressed this week. I'll tell u m life story because it feels goo when I get advise on my life. I was sorta molested around 5-6 grade. I didn't really know what I was doing. He would just touch me there and I would be like... Wow that's odd, but I didn't try to stop. But I'm not a fag or anything. One day he pinned me down and told me to kiss him and I think that's when I knew something was up. So I told my parents. He was in 8th grade. Before that happened I met this guy that was a senior and he played yugio cards like I did so I thought he was cool. He lived close so I invited him over to come over with my friends and play some. He saw my mom an had a crush on her. So because I brought him in my house he met my mom. Anyways he got to know my parents and he ended up be so friendly that he moved in because his guardian was a phyco and he needed help with school. He seemed pretty cool but I think that I was getting old enough to notice that my mom was acting different. He would get mad at me cause I annoyed me and he hit me with a pillow really hard and she didn't do a fuoking thing. Anyways I'll skip alot and after the cops being called a few times my mom divorced my dad. She dosebt pay child support. And me, my sister, and my lil bro were stuck here and it was hard to get the bills paid. My sister didn't help either. It all started out with her along time before that. When I was real small she used to tell me she would get me something if I let her friend, who wasent supposed to be in the house because she was a slut and was a druggie, come in. And if I didn't she would get mad and act like I did something wrong. Even to this day she still has the same principle attitude toward that situation. My brother is the one I feel worst about he was only 5 and he was to small to be in that junk. Now my dad remarried and his new wife is very sensetive and I know there is nothing wrong with that but it is very stressful to deal with. My mom is how an alcoholic and is a big smoker. I want to tell my sister and mom off so bad but I am afraid to because my mom was kinda sucidal and i don't want to go back to that. And when ever I try to talk to my sister she is always right even when she is wrong. Is there any advise on what I should do?